We present the rationale for and design of a randomized, open-label, active-control trial comparing the effectiveness of 200. units of onabotulinum toxin A (Botox A®) versus sacral neuromodulation (InterStim®) therapy for refractory urgency urinary incontinence (UUI). The Refractory Overactive Bladder: Sacral N. Euromodulation vs. Bo. Tulinum Toxin Assessment (ROSETTA) trial compares changes in urgency urinary incontinence episodes over 6. months, as well as other lower urinary tract symptoms, adverse events and cost effectiveness in women receiving these two therapies. Eligible participants had previously attempted treatment with at least 2 medications and behavioral therapy. We discuss the importance of evaluating two very different interventions, the challenges related to recruitment, ethical considerations for two treatments with significantly different costs, follow-up assessments and cost effectiveness. The ROSETTA trial will provide information to healthcare providers regarding the technical attributes of these interventions as well as the efficacy and safety of these two interventions on other lower urinary tract and pelvic floor symptoms. Enrollment began in March, 2012 with anticipated end to recruitment in mid 2014. © 2014 Elsevier Inc.